Make config errors more important during init operations (#33628)

* make config errors more important during init operations

* address comments

internal/command/init.go

@@ -262,24 +262,25 @@ func (c *InitCommand) Run(args []string) int {
 		return 1
 	}
 
-	// If we pass the core version check, we want to show any errors from initializing the backend next,
-	// which will include syntax errors from loading the configuration. However, there's a special case
-	// where we are unable to load the backend from configuration or state _and_ the configuration has
-	// errors. In that case, we want to show a slightly friendlier error message for newcomers.
-	showBackendDiags := back != nil || rootModEarly.Backend != nil || rootModEarly.CloudConfig != nil
-	if showBackendDiags {
-		diags = diags.Append(backDiags)
-		if backDiags.HasErrors() {
-			c.showDiagnostics(diags)
-			return 1
-		}
-	} else {
-		diags = diags.Append(earlyConfDiags)
-		if earlyConfDiags.HasErrors() {
-			c.Ui.Error(strings.TrimSpace(errInitConfigError))
-			c.showDiagnostics(diags)
-			return 1
-		}
+	// We've passed the core version check, now we can show errors from the
+	// configuration and backend initialisation.
+
+	// Now, we can check the diagnostics from the early configuration and the
+	// backend.
+	diags = diags.Append(earlyConfDiags)
+	diags = diags.Append(backDiags)
+	if earlyConfDiags.HasErrors() {
+		c.Ui.Error(strings.TrimSpace(errInitConfigError))
+		c.showDiagnostics(diags)
+		return 1
+	}
+
+	// Now, we can show any errors from initializing the backend, but we won't
+	// show the errInitConfigError preamble as we didn't detect problems with
+	// the early configuration.
+	if backDiags.HasErrors() {
+		c.showDiagnostics(diags)
+		return 1
 	}
 
 	// If everything is ok with the core version check and backend initialization,
@@ -1187,7 +1188,8 @@ func (c *InitCommand) Synopsis() string {
 }
 
 const errInitConfigError = `
-[reset]There are some problems with the configuration, described below.
+[reset]Terraform encountered problems during initialisation, including problems
+with the configuration, described below.
 
 The Terraform configuration must be valid before initialization so that
 Terraform can determine which modules and providers need to be installed.

internal/command/init_test.go

@@ -2642,7 +2642,7 @@ func TestInit_invalidSyntaxNoBackend(t *testing.T) {
 	}
 
 	errStr := ui.ErrorWriter.String()
-	if subStr := "There are some problems with the configuration, described below"; !strings.Contains(errStr, subStr) {
+	if subStr := "Terraform encountered problems during initialisation, including problems\nwith the configuration, described below."; !strings.Contains(errStr, subStr) {
 		t.Errorf("Error output should include preamble\nwant substr: %s\ngot:\n%s", subStr, errStr)
 	}
 	if subStr := "Error: Unsupported block type"; !strings.Contains(errStr, subStr) {
@@ -2671,7 +2671,7 @@ func TestInit_invalidSyntaxWithBackend(t *testing.T) {
 	}
 
 	errStr := ui.ErrorWriter.String()
-	if subStr := "There are some problems with the configuration, described below"; !strings.Contains(errStr, subStr) {
+	if subStr := "Terraform encountered problems during initialisation, including problems\nwith the configuration, described below."; !strings.Contains(errStr, subStr) {
 		t.Errorf("Error output should include preamble\nwant substr: %s\ngot:\n%s", subStr, errStr)
 	}
 	if subStr := "Error: Unsupported block type"; !strings.Contains(errStr, subStr) {
@@ -2700,17 +2700,49 @@ func TestInit_invalidSyntaxInvalidBackend(t *testing.T) {
 	}
 
 	errStr := ui.ErrorWriter.String()
-	if subStr := "There are some problems with the configuration, described below"; strings.Contains(errStr, subStr) {
-		t.Errorf("Error output should not include preamble\nwant substr: %s\ngot:\n%s", subStr, errStr)
+	if subStr := "Terraform encountered problems during initialisation, including problems\nwith the configuration, described below."; !strings.Contains(errStr, subStr) {
+		t.Errorf("Error output should include preamble\nwant substr: %s\ngot:\n%s", subStr, errStr)
 	}
-	if subStr := "Error: Unsupported block type"; strings.Contains(errStr, subStr) {
-		t.Errorf("Error output should not mention syntax errors\nwant substr: %s\ngot:\n%s", subStr, errStr)
+	if subStr := "Error: Unsupported block type"; !strings.Contains(errStr, subStr) {
+		t.Errorf("Error output should mention syntax errors\nwant substr: %s\ngot:\n%s", subStr, errStr)
 	}
 	if subStr := "Error: Unsupported backend type"; !strings.Contains(errStr, subStr) {
 		t.Errorf("Error output should mention the invalid backend\nwant substr: %s\ngot:\n%s", subStr, errStr)
 	}
 }
 
+func TestInit_invalidSyntaxBackendAttribute(t *testing.T) {
+	td := t.TempDir()
+	testCopyDir(t, testFixturePath("init-syntax-invalid-backend-attribute-invalid"), td)
+	defer testChdir(t, td)()
+
+	ui := cli.NewMockUi()
+	view, _ := testView(t)
+	m := Meta{
+		Ui:   ui,
+		View: view,
+	}
+
+	c := &InitCommand{
+		Meta: m,
+	}
+
+	if code := c.Run(nil); code == 0 {
+		t.Fatalf("succeeded, but was expecting error\nstdout:\n%s\nstderr:\n%s", ui.OutputWriter, ui.ErrorWriter)
+	}
+
+	errStr := ui.ErrorWriter.String()
+	if subStr := "Terraform encountered problems during initialisation, including problems\nwith the configuration, described below."; !strings.Contains(errStr, subStr) {
+		t.Errorf("Error output should include preamble\nwant substr: %s\ngot:\n%s", subStr, errStr)
+	}
+	if subStr := "Error: Invalid character"; !strings.Contains(errStr, subStr) {
+		t.Errorf("Error output should mention the invalid character\nwant substr: %s\ngot:\n%s", subStr, errStr)
+	}
+	if subStr := "Error: Invalid expression"; !strings.Contains(errStr, subStr) {
+		t.Errorf("Error output should mention the invalid expression\nwant substr: %s\ngot:\n%s", subStr, errStr)
+	}
+}
+
 func TestInit_tests(t *testing.T) {
 	// Create a temporary working directory that is empty
 	td := t.TempDir()

internal/command/meta_backend.go

@@ -19,6 +19,9 @@ import (
 
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/hcldec"
+	"github.com/zclconf/go-cty/cty"
+	ctyjson "github.com/zclconf/go-cty/cty/json"
+
 	"github.com/hashicorp/terraform/internal/backend"
 	"github.com/hashicorp/terraform/internal/cloud"
 	"github.com/hashicorp/terraform/internal/command/arguments"
@@ -29,8 +32,6 @@ import (
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 	"github.com/hashicorp/terraform/internal/terraform"
 	"github.com/hashicorp/terraform/internal/tfdiags"
-	"github.com/zclconf/go-cty/cty"
-	ctyjson "github.com/zclconf/go-cty/cty/json"
 
 	backendInit "github.com/hashicorp/terraform/internal/backend/init"
 	backendLocal "github.com/hashicorp/terraform/internal/backend/local"
@@ -1398,6 +1399,14 @@ func (m *Meta) backendInitFromConfig(c *configs.Backend) (backend.Backend, cty.V
 		return nil, cty.NilVal, diags
 	}
 
+	if !configVal.IsWhollyKnown() {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Unknown values within backend definition",
+			"The `terraform` configuration block should contain only concrete and static values. Another diagnostic should contain more information about which part of the configuration is problematic."))
+		return nil, cty.NilVal, diags
+	}
+
 	// TODO: test
 	if m.Input() {
 		var err error

internal/command/testdata/init-syntax-invalid-backend-attribute-invalid/main.tf

@@ -0,0 +1,10 @@
+
+terraform {
+  backend "local" {
+    path = $invalid
+  }
+}
+
+variable "input" {
+  type = string
+}